We present a series of 247 undisplaced femoral neck fractures, of which 122 were primarily treated non-operatively, and 125 with primary operative stabilization. The background parameters did not differ significantly in the two groups. The length of hospitalization was 1 week shorter in the operatively treated group. They started to walk bearing full weight at an average of 11 days earlier. Two-thirds of the operatively treated but only one-quarter of the non-operatively treated patients were able to walk alone when they left hospital. General complications were recorded in 19 of the non-operatively and in four of the operatively treated patients during their hospitalization. Early displacement (within 6 weeks) was noted in 20 per cent of the non-operatively treated patients who required late operation. However, there was no early displacement in the operatively treated group. We therefore recommend primary operative stabilization of undisplaced femoral neck fractures.